Known jetted bath tubs include a pump having a pump motor. The pump motor typically is an electric AC motor having start-and run windings. Energization of the motor windings is controlled, at least in part, by an operator actuated control switch and a centrifugal switch. The operator actuated control switch for jetted bath tub applications typically is an air switch. The centrifugal switch controls cut-out of the motor start winding based on rotor speed during motor start-up.
One known air switch used in jetted tub applications is a "push to start, push to stop" type air switch. The known air switch includes a normally open snap action switch and a spring-biased actuator. The snap action switch is electrically connected in series with a power line and the common connection of the pump motor start and run windings. The snap action switch includes a movable, spring-biased button which extends from the snap action switch housing. The button is normally biased to be in a fully extended condition, and when the button is fully extended, the snap action switch is in an open state. When the button is fully depressed inward towards the housing, the snap action switch is in a closed state.
The spring-biased actuator includes an actuating arm movable from and between first and second positions. In the first position, the actuating arm does not contact the snap action switch button. In the second position, the actuating arm is in contact with, and fully depresses, the snap action switch button. The actuator is biased so that the actuator arm is normally in the first position.
The air switch also includes an operator controlled air transmitter coupled to an air bellows. The transmitter includes a user depressible flexible diaphragm. When an operator presses against, and deforms, the flexible diaphragm, a pulse of air is delivered to the air bellows and causes the bellows to expand. The bellows acts against the actuator, and when the bellows expands, the position of the actuator changes. The air transmitter typically is located near or integral with the tub so that an operator in or next to the tub can depress the switch to initiate or stop pump operation.
More specifically, to initiate pump operation with the above described air switch, the operator depresses the air transmitter flexible diaphragm and a pulse of air from the air transmitter causes the air bellows to expand. The bellows acts against the actuator and causes the actuator to move from the first position to the second position. The actuator is latched into the second position and, as described above, depresses the button of the snap action switch. When the snap action switch button is depressed, the snap action switch closes and energy is delivered to the motor start and run windings through the power line.
Once the pump motor rotor reaches a predetermined speed during motor start-up, the centrifugal switch opens and the start winding is de-energized. The motor then operates with only the run winding energized.
To stop pump operation, the user again depresses the air transmitter flexible diaphragm and a pulse of air from the air transmitter again causes the air bellows to expand. The bellows acts against the actuator and causes the actuator to "unlatch" and move from the second position to the first position. As described above, the button of the snap action switch is not depressed when the actuator is in the first position. When the snap action switch button is not depressed, the snap action switch opens and the pump motor windings are de-energized.
The above described jetted bath tub pump motor application is referred to as a "user attended" application since the user has direct control over motor energization. There are many other "user attended" applications in addition to the jetted bath tub pump motor application.
Although the above described motor has proven reliable and satisfactory, it would be desirable to reduce the cost of such motor, in terms of both component cost and assembly cost. Particularly, eliminating the centrifugal switch would result in significant cost savings since the centrifugal switch is expensive. The centrifugal switch, however, controls energization of the start winding and such control is necessary for efficient motor operation during both motor start-up and run operations.
With respect to manufacture and assembly of the above described jetted tub motor, since the motor type for a jetted bath tub pump application generally is also utilized in other applications, the motor is manufactured and mostly assembled in a common assembly line with many other motors used for other applications. At a late point in assembly, motors for the jetted tub pump application are separated from the other motors on the line, and the air switch and power cord are added to the separated motors for the jetted tub pump application.
Since the air switch and power cord are added late in the assembly process, the air switch and the power cord typically are not mounted within the motor housing. Rather, the air switch and a portion of the power cord are housed within a removable cover which is removably secured to the motor endshield. The removable cover for the air switch and power cord, in one known form, is a molded thermoplastic housing.
Cost savings could potentially be realized by eliminating the above described removable cover. Due to the late point assembly of the air switch and power cord to the motor, however, the removable cover is required to protect these components and connections.
Accordingly, it would be desirable and advantageous to provide a low cost motor for jetted tub and other user attended applications. It would also be desirable and advantageous to provide such a low cost motor which is as reliable and safe as existing motors for user attended applications.
An object of the present invention is to provide a low cost motor for user attended applications, including for jetted tub pumps, by at least eliminating the centrifugal switch for controlling energization of the motor start winding.
Another object of the present invention is to eliminate the motor centrifugal switch without adversely affecting motor operation.
Still another object of the invention is to eliminate the removable cover for the air switch and associated power cord portion.